It's tough to look at projections for Aceves as a closer because everyone has projected him as starting some games as well, which drives up ERA. And it's tough to look at projections for Melancon because Ron Shandler and Bill James projected him as an Astro.
Be that as it may, you can adjust for both factors, figuring that ERA in a start is 0.80 higher than a relief appearance, and that moving from the NL to the AL adds 6% to ERA (above and beyond the park factors).
In which case none of the major sources projects Melancon to be better than Aceves.
PECOTA 3.61, 4.09
ZiPS 3.40, 3.59
BJ 3.30, 4.37
RS 3.40, 3.69
However, given Aceves' multi-inning versatility, if ZiPS or Shandler were correct, you'd probably have Melancon close.
Both projections have very wide error bars, Aceves because of the BABIP factor and Melancon because of his possible second-half breakthrough last year, and the league switch.
I wouldn't put it beyond Bobby V to dismiss "closer by committee" as an option and then do it to at least some degree, e.g., naming Aceves as closer and making some excuse each time he went with Melancon on a given day. The real reason might be that they feel Melancon is the better option against weak hitters, while Aceves is a much better one against tough lineup stretches, but they'd talk about simply managing Aceves' total use instead.
Another, similar strategy would be to name Melancon the closer and Aceves the setup man (which is to say relief ace), but with the announced caveat that because of Aceves' multi-inning capability, there will be days when he'll take the 8th and
9th. And then do that an awful lot, essentially restricting Melancon to easy saves. That would my initial plan.
Finally, if Bailey is really out until the second half, you have to think about Rich Hill as a dark horse candidate. Not saying that he should even be "given a chance," but that of all the guys on the roster, he's one that has shown, very briefly, that he might conceivably be better than both Aceves and Melancon.
Edited by Eric Van, 03 April 2012 - 05:26 AM.